Add helpful information (# of adults, kids ages, allergies, recipient contact information) for volunteers so that they have all the information they need. This will cut down on calls/emails to the organizer.
2 - Share the unique Meal Plan link
Each meal plan will come with a unique sharing link (i.e. http://mealmein.com/helpout/<secret code>)
Share that link however you want - email, facebook, twitter, etc...
The link is public - so anyone who has the link can view the meal plan. But the secret code is random, so its unlikely someone will stumble upon your meal plan.
3 - Volunteers sign up and receive e-mail reminders
With the sharing link in hand, volunteers can view the meal plan, find open meals slots, and reserve them.
Volunteers will receive a reminder email a few days before their scheduled day. (The default is three days, but you can customize it.)
Meal recipients will receive an email the day before with a list of meals that they are scheduled to receive.